1. Field
The present disclosure generally relates to methods and apparatus for adapting channel estimation in a communication system, and more particularly to adapting channel estimation schemes to optimize channel estimation in high Doppler environments.
2. Background
In particular wireless networks including those operating using Orthogonal Frequency Division Multiplexing (OFDM), a receiver in such networks may utilize channel estimation to accurately recover transmitted data. That is, the channel estimate models the wireless transmission channel to account for amplitude and phase shifts due to the frequency selective and time-varying nature of the channel to afford accurate time tracking, and thus demodulation of a signal. In certain communication systems, channel estimation may be assisted by transmitting reference values or pilot signal in predetermined subcarrier frequencies, where the pilot signals are then used to calculate the channel estimate.
Since the channel estimate is important for accurately recovering the transmitted data, degradation in the quality of the channel estimation presents deleterious effects to demodulation and decoding of transmitted data. One factor known to degrade the channel estimation is increased speeds of a receiver relative to the transmitter (i.e., high Doppler environments). In order to account or correct for this degradation to maintain channel estimation quality, it is known to tune the channel estimation scheme to the Doppler by performing a correlation to determine how quickly the received waveform changes. Optimizing the channel estimation scheme, however, is difficult at higher speeds. Accordingly, enhancement of performance of the channel estimation for higher speeds through improved optimization is desirable.